Psalm 15 starts with a question: Lord, who may dwell in your sanctuary? Who may live on your holy hill? While this psalm of entry is focused on the sacred precincts of the Jerusalem Temple, the answer lies outside the Temple. The specific instructions are rather broad, addressing the priority of conducting relationships in a particular way. Presumably, if you can get relations with others correct, you're understanding God's expectations, and are worthy for your pursuit of true righteousness.
In James' epistle, he is writing to Christians who are concerned about their standing when the imminent Day of Judgment arrives. They may have a scrupulousness that wants to avoid doing the wrong thing, creating a new kind of purity code. Their extremism seems to produce the response in James that seeks to balance the new moral purity code with an ethic of conduct and behavior. He insists on the synchronization of the purity code with an action-based, daily-lived faithfulness.
Both scriptures press the question of having the right spirituality to be found worthy by God. Both responses take pains to show that spiritual integrity only matters when it has real life application. Only in that way to reflect God's desires and the way of the Lord's Kingdom.
Check out the sermon video below (Oh, c'mon, YouTube! That thumbnail pic is just wrong) and the downloads below the video panel.